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Constraints & Concepts Basic Assembly Constraints & Concepts

Assembly constraints are parameters that define the geometric relationships between components in a CAD assembly. These constraints include: Mate/Flush Angle Tangent Insert

A component floating in space has six degrees of freedom: 3 rotations around the X, Y, and Z axes. 3 translations along the X, Y, and Z axes. Degrees of freedom are systematically removed in an assembly until only the desired components are allowed to move.

Mate Constraint Constrains two faces, edges, points, or axis together. The red arrows represent normal vectors and point towards each other.

Flush Constraint Constrains two faces or work features together. Normal vectors will point in the same direction.

Angle Constraint Constrains two faces or edges at an angle to one another. Normal vectors parallel to each other equal 0° angle.

Insert Constraint Constrains a cylinder flush into a hole.

Tangent Constraint Constrains a curved surface to a plane or another curved surface.

Base Component The first component placed in an assembly should be a fundamental part or sub-assembly, such as a frame or base plate, on which the rest of the assembly is built. The first component in an assembly file sets the orientation of all subsequent parts and subassemblies.

Grounded Component When the first component is placed in the assembly, its origin is coincident and aligned with the assembly coordinate origin. All degrees of freedom are removed from the first component. The base component will be grounded and should be left that way.

Patterning Component This function duplicates one or more components and arranges the resulting occurrences in a circular or rectangular pattern.

Replace Component In the design process, one often needs to replace one or more components in an assembly. The new component is placed in the same location as the original component, but assembly constraints may be deleted in the process.

Editing Components When you double click on a component, you will exit the assembly environment and enter the part environment. The other components in the assembly will become translucent. When you are finished editing the part, you will exit the part environment and return to the assembly environment.

Subassemblies A group of components that are constrained to act as one component in a larger assembly.